Differential pulley-block



ll/4 l llllll J. HOLT.

DIFFERENTIAL PULLEY BLOGK.

(No Model.)

C2/2R65.; es

UNITED STATES PATENT OEEICE.

JOSEPH HOLT, OF ORADLEY HEATH, COUNTY OF STAFFORD, ENGLAND, ASSIGNOR TO DAVID ROUND da SON, OF CLEVELAND, OHIO.

DIFFERENTIAL PU LLEY-BLOCK.

SPECIFICATION forming' part of Letters Patent No. 428,675, dated May 27, 1890.

Application filed February 7.1890. Serial No. 339,513. (No model.)

To all whom it may concern.-

Be it known that I, JOSEPH IIOLT, of Cradley Heath, in the county of Staford, England, have invented certain new and useful Improvements inDiiierentialPulley-Blocks; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it pertains to make and use the same.'

My invention relates to improvements in diiferential pulley-blocks, the no vel feature comprising a chain-guide, consisting of an arm pivoted to the frame or easing of the sprocket-blook, so as to turn in the same plane as the sheave on which the hand-chain winds, the free end of such arm being provided with a loop through which the chain passes loosely, whereby the chain is kept from'twisting and is properly guided in its movements to and from the sheave.

In the accompanying drawings, Figure 1 is an edge View. Fig. 2 is a side elevation. .Fig 3 is an enlarged elevation in detail. Fig. 4 is an enlarged bottom plan in detail.

The differential pulley-block, one of which is shown at A, may be substantially as heretofore Constructed, except that the frame or easing of bleek A has provision for pivotally attaching arm B at a, so that the arm may swing in the same plane as the. sprocketwheel that is opposite the arm, and on which sheave the hand-chain Winds. Arm B, at the free end thereof, has a loop Z1, adapted to re eeive the chain loosely, as shown more clearly in Fig. 4t. The one side of the loopis slotted at b the entire length of the loop for receiving the chain. To enter the hand-chain in the loop, one link thereof is turned at right angles with the axisof the loop,'and such link is advanced through the slot. (See Fig. 3.) The loop holds the chain from twisting and at the same time guides the chain in its movements to and from the sheave, and this, too, regardless of the lead ofv the hand-chain, Whether leading horizontally, vertically, or at any intermediate angle.

The device is simple, inexpensive, and efcient.

The combination,with a differential pulleyblock, of a Chain-guide comprising an arm pivoted to the sprocket-block, so as to turn in the same plane as the opposing sheave, the free end of such arm having a loop adapted to fit the chain loosely, such loop having a slotted side for entering the chain, substantially as set forth.

In testimony whereof I sign this specification in the presence of two witnesses, this 12th day of November, 1889.

JOSEPH HOLT.

Nitnessesz F. M. BURTON, E. HARKER. 

